Foam board insulation is easy to use and a great DIY way to add some insulation. It comes in standard-size 4×8 sheets and smaller sizes, in thicknesses from 1/4-in. to two inches. Some types of ...

Compared to plywood, the polyurethane foam boards have several advantages: Lightweight: The foam boards weigh 30 to 60% less than the same sized plywood sheet.